Relating NDT data to mechanical performance loss in Impact-damaged composites

摘要

There is currently no accepted method of incorporating non-destructive test data, gained from the inspection of impact-damaged composites directly into finite element models capable of predicting remaining mechanical performance. An improved ability to relate non-destructive testing data to performance is vital to allow damaged composites to be assessed rapidly and effectively prior to continued use, repair or replacement. This paper presents finite element simulations of the compression after impact tests performed on polymer-matrix composite laminates reinforced by unidirectional carbon fibres. These tests are performed on laboratory coupons, which are monolithic, flat, rectangular composite plates with conventional stacking sequences. The tests are simulated using conventional failure criteria for fibre, matrix damage and interlaminar delamination. Ultrasonic data acquired from the impact-damaged panels are incorporated automatically into the simulations to generate the initial condition of the laminates in terms of delaminations and matrix cracks. Good correspondence is achieved between simulation and experiment for aspects such as force-displacement responses, and buckling behaviour prior to final failure.